Optical devices are widely used for sensing different properties. Such optical devices may comprise optical fibres that have sensing regions in which a change in a property causes a change in an optical condition for guiding light in the optical fibres.
For example, an optical device may be arranged for sensing changes in temperature, strain or pressure and may comprise a Bragg grating which has an optical response that depends on the strain of the Bragg grating. A change in an external pressure or temperature may cause a change in strain of the Bragg grating, which in turn causes a change in a light interference condition. Consequently, the change in external pressure or temperature can be detected by monitoring an optical response of the Bragg grating.
The optical device may comprise any number of optical fibres with or without Bragg gratings. For example the optical device may comprise a pair of optical fibres. One optical fibre may be arranged for sensing a first property and another property may be arranged for sensing a second property. However, such optical devices having a pair of optical fibres have the disadvantage that mechanical bending flexibility of the device is reduced in a plane in which the optical fibres are positioned.
There is a need for technological advancement.